1. Technical Field
The present invention relates to a liquid crystal projector that enlarges and displays images on a screen or the like, and, more particular, to a cooling technique of a liquid crystal projector.
2. Related Art
In a projection liquid crystal projector of the related art, an optical image (image light) is formed by a light modulating device, for example, a liquid crystal panel, that modulates light flux emitted from a light source based on image information, and an image is displayed by projecting the image light on a screen or the like. With respect to a lamp, for example, a halogen lamp, which is used for a light source, generates a large amount of heat when the light source light is irradiated. Therefore, when a liquid crystal panel exceeds an allowable temperature due to the strong heat of a light source, display properties deteriorate and the life span thereof becomes short.
In particular, in recent years, there is a tendency to use a light source lamp which has larger output in order to increase the luminance of a projection image, and thus it is necessary to further improve the cooling efficiency of a cooling device built in a liquid crystal projector.
In the related art, a cooling device built in such a liquid crystal projector generally includes a cooling fan that blows outside air into a liquid crystal panel. However, if the amount of blowing is increased by increasing the rotation speed of a cooling fan or the size of the fan with the increase in the output of the light source lamp as described above, the noise or the vibration of the liquid crystal projector increases, so that the amenity of the installation environment is impaired and the components of the liquid crystal projector are adversely affected.
Therefore, for example, JP-A-8-194201 discloses a liquid crystal projector in which a thermoelectric conversion material, for example, a Peltier element, is provided in a cooling device, and heat in the housing of the liquid crystal projector is absorbed, thereby improving cooling efficiency. Therefore, cooling can be effectively performed even though the size and the rotation speed of a cooling fan are not increased.
However, as in the liquid crystal projector disclosed in JP-A-8-194201, if a Peltier element is used in a cooling device, there is a problem in that dew condensation easily occurs in the cooling side (low temperature section) of the Peltier element. In particular, condensed water drops increase in summer when the outside humidity increases, and water drops are scattered by a cooling fan, so that there are problems in that the liquid crystal panel may be polluted and electrical failure may occur.